This invention relates to a wrench and more particularly to an open-end wrench having the gripping capability of box end wrench or flare nut wrench combined with the flexibility of a ratchet wrench in one wrench.
The classes of wrenches including open end wrenches, box or closed end wrenches, flare nut wrenches, spanner or adjustable wrenches, and ratchet wrenches are extremely useful in certain areas. However, there are some areas where the design of the particular class of wrench precludes its use. For example, an open end wrench can have access to many nuts, which other classes of wrenches cannot reach or, on which, the other classes cannot be used.
Yet this access feature of the open end wrench causes other problems. The normal open end wrench has only two points of contact with the hex nut or bolt head. If the nut or bolt turns with considerable resistance, the normal open end wrench can slip and round the points off of the nut or bolt head. The box end wrench provides six or twelve point gripping for a nut--thereby minimizing or eliminating the change of slipping or rounding off the points.
The mixture of English-sized nuts and metric-sized nuts used today causes additional problems. The open end or fixed end wrench must be precisely sized to fit the nut or bolthead. This causes problems because the closeness of size between certain metric and English sizes is sufficiently different to require different fixed wrenches. It is desirable to have a wrench with closed end capabilities also to have the capability of fitting closely-sized English or metric nuts.
There are cases where a bolt head or a nut is partially covered by an object or blocked in another fashion, which makes it impossible to place a box end thereover. Also, there are also situations a nut is on a threaded rod protected by brackets or other devices on each end of the rod which do not allow a box end wrench to be placed over the nut. An open end wrench, with all of its inherent disadvantages must be used in these cases.
A disadvantage of both the open end wrench and closed end wrench (a generic name for open and closed end wrenches being fixed end wrenches) becomes apparent, when a fixed end wrench is used on a worn nut or bolt, or a nut or bolt with a slight size variation as occasionally occur during manufacture. Such variations, whether caused by wear or manufacturing differences, can render the use of the fixed end wrench impossible.
Additionally rusted or frozen nuts usually cannot be loosened by the standard open end wrench. The normal open end wrench, with its two point gripping power, can slip and round off the points of the nut or bolt head. This increased damage adds to the problems of removing the nut.
There are problems with the use of a flare nut wrench too, even though a flare nut wrench can provide more gripping points when used in a proper fashion than can an open end wrench. If the flare nut or fitting turns hard, the flare nut wrench is a very time-consuming tool to use. A ratchet wrench can simplify this problem, but a ratchet wrench has no access to a flare nut.
It thus becomes clear that it is advantageous to combine features of the open end wrench with features of the other wrenches to achieve very desirable results.